The present invention concerns generally the provision of an indicator assembly serving to signal the presence of pressurized gas in a gas supply line serving a using instrumentality.
A problem encountered by those using pressurized gas from a tank is the failure to shut off the gas supply and depressurize the supply line or conduit between the source and the using instrumentality, for example, a welding torch or a propane burner. In the interest of safety and economy it is of course always desirable to shut off a gas flow at the tank, a practice not always followed by gas users. While shutting off and depressurizing a gas supply line upon termination of a welding or other gas using operation is desirable, such may be overlooked with the result that line remains pressurized subjecting same to possible leaking. While pressure regulators in supply lines indicate line and/or tank pressure inspection of same at the end of a task is not always done. Still further, a malfunctioning control valve on an oxygen or propane tank could pressurize a non-operating gas supply line.
U.S. Pat. No. 4,121,615 discloses a mechanical indicator indicating loss of pilot gas pressure with provision for closing off communication between a fluid source and a remote actuator or valve. The valve control disclosed is operable by pilot presence and includes manual resetting of a valve stem to re-establish a primary gas flow.
U.S. Pat. No. 4,450,721 provides a method and an apparatus for indicating the weight and quantity of fuel in a storage container.
U.S. Pat. No. 4,596,980 discloses a valve having a stem responsive to pilot gas pressure and which stem, in the absence of pilot pressure, moves downwardly to permit a battery to energize an LED to indicate pilot pressure loss.